Burner for a gas turbine

Abstract

A burner for a gas turbine, wherein the burner has a combustion chamber, a preheating device adapted to preheat air before it enters the combustion chamber and a swirler adapted to guide a swirler air flow that has the preheated air to the combustion chamber, wherein the swirler has a base plate with a surface that confines the swirler air flow, wherein the surface has a hole adapted to inject a liquid fuel into the swirler air flow and the base plate has a channel for transporting the liquid fuel to the hole, wherein at least a part of the channel is oriented essentially parallel to the surface so that the liquid fuel streams essentially parallel to the surface and is preheated by the swirler air flow.

1 . A burner for a gas turbine, wherein the burner comprises:
 a combustion chamber, and   a swirler,   wherein the swirler comprises an annular array of vanes extending from a base plate which define an annular array of passages for guiding a swirler airflow, the base plate defines a surface of the passage over which the swirler air flow flows,   wherein the surface has a hole adapted to inject a liquid fuel into the swirler air flow and the base plate has a channel for transporting the liquid fuel to the hole,   wherein at least a part of the channel is oriented essentially parallel to the surface so that the liquid fuel is streamed essentially parallel to the surface and is preheated.   
     
     
         2 . The burner according to  claim 1 ,
 wherein the part of the channel which is oriented essentially parallel to the surface has a distance to the surface from 2 mm to 10 mm.   
     
     
         3 . The burner according to  claim 1 ,
 wherein the diameter of the hole is from 0.5 mm to 3 mm.   
     
     
         4 . The burner according to  claim 1 ,
 wherein the diameter of the channel in a plane perpendicular to the flow direction of the liquid fuel is from 0.5 mm to 3 mm.   
     
     
         5 . The burner according to  claim 1 ,
 wherein the material of the base plate consists of carbon steel and/or steel with 1 weight-% carbon.   
     
     
         6 . The burner according to  claim 1 ,
 wherein the base plate with the channel is formed by electronic discharge machining, selective laser sintering and/or selective laser melting.   
     
     
         7 . The burner according to  claim 1 ,
 wherein the base plate comprises two joint plates, wherein each plate comprises recesses that form a part of the channel.   
     
     
         8 . The burner according to  claim 1 ,
 wherein the channel has the shape of a spiral.   
     
     
         9 . The burner according to  claim 1 ,
 wherein the channel has a meandering shape.   
     
     
         10 . The burner according to  claim 1 , further comprising:
 a compressor for compressing the air before it enters the combustion chamber, whereby the temperature of the air raises and the compressor forms the preheating device.   
     
     
         11 . The burner according to  claim 1 , further comprising:
 a further wall confining the swirler air flow on the same side as and upstream with respect to the swirler air flow from the base plate and being displaced with respect to the base plate in a direction towards the swirler air flow so that a step being able to cause a flow separation of the swirler air flow is formed by the base plate.   
     
     
         12 . The burner according to  claim 1 ,
 wherein the combustion chamber is essentially rotationally symmetric around a burner axis and the step is located at a radial distance from the burner axis which is from r 1 +0.2*(r 2 −r 1 ) to r 1 +0.8*(r 2 −r 1 ), wherein r 1  is the radial distance from the burner axis to the radial inner end of the swirler and r 2  is the radial distance from the burner axis to the radial outer end of the swirler.   
     
     
         13 . The burner according to  claim 1 ,
 wherein the height of each step is from 0.2*L to 0.5*L, wherein L is the distance from the step to the hole.   
     
     
         14 . The burner according to  claim 1 ,
 wherein the height of each step is maximum 15% of the swirler channel height (H), wherein the swirler channel height (H) is the distance from the further wall to an opposite wall confining the swirler air flow and facing towards the base plate.   
     
     
         15 . The burner according to  claim 1 , further comprising:
 a preheating device adapted to preheat air before it enters the combustion chamber and the swirler adapted to guide the swirler air flow that comprises the preheated air to the combustion chamber.